Monthly Archives: June 2010

How to manage Google AppEngine maintenance periods

AppEngine logoHere is a small snippet of code that I use on applications deployed on Google AppEngine to inform users that the application is in maintenance mode.

It usually happen when the AppEngine team put the datastore in read-only mode for maintenance purpose but other capabilities can be tested as well.

This is a python decorator and you can use it to decorate views that require write access to the datastore. For example:

You will need to create a Django template named maintenance.html to display a warning to your users. Mine looks like this:

Properly uploading files to Amazon S3

Here is a little script I wrote and I though ought to be shared. I use it to upload static files like images, css and javascript so that they can be served by Amazon S3 instead of the main application server (like Google App Engine).

It’s written in Python and does interesting things like compressing and minifying what needs to be. It takes 3 arguments and as 2 options:

src_folder
path to the local folder containing the static files to upload
destination_bucket_name
name of the S3 bucket to upload to (e.g. static.example.com)
prefix
a prefix to use for the destination key (kind of a folder on the destination bucket, I use it to specify a release version to defeat browser caching)
x
if set, the script will set a far future expiry for all files, otherwise the S3 default will be used (one day if I remember well)
m
if set, the script will minify css and javascript files

First you will have to install some dependencies, namely boto, jsmin and cssmin. Installation procedure will depend on your OS but on my Mac I do the following:

And here is the script itself:

Thanks to Nico for the expiry trick :)